Making Boot Media
We’ll cover booting the OpenBSD installer from a CD or floppy disk. Generally, booting via CD is preferable because all amd64 systems can boot from CD, as can most functioning i386 systems. We’ll start by making floppies for installation on old i386 hardware and then move on to CDs. While installing from USB and into virtual systems is possible, neither is supported. We’ll cover both of those installation types later in the book, in Chapter 23.
Making Boot Floppies
You need to make boot floppies only if your hardware does not boot from CD, or if you have a floppy but not a CD drive. The OpenBSD boot floppies contain a very limited subset of OpenBSD—just enough to recognize your hardware, format your disk, and download and extract the file sets. In addition to the floppies themselves, you’ll also need a working Internet connection via Ethernet.[8] Because the full kernel is larger than a single floppy can hold, OpenBSD provides three floppy images for i386 hardware, each targeting a specific type of hardware. Each image name includes the release number. For example, the floppy images for release 5.3 are named floppy53.fs, floppyB53.fs, and floppyC53.fs. Download the image that most closely describes your system, as follows:
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floppyXX.fs. This is the image for the most common i386 hardware. It will boot the average workstation or low-end server.
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floppyBXX.fs. This image includes drivers for gigabit Ethernet cards, SCSI, and RAID. It’s meant for higher-end i386 servers.
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floppyCXX.fs. This image supports PCMCIA and CardBus. It’s meant for laptops.
OpenBSD provides only one floppy image for amd64 hardware: floppyXX.fs. (The amd64 platform doesn’t carry around 20 years of legacy drivers as baggage, so everything fits on a single disk.) Be sure to use the floppy image found in the amd64 directory. The amd64 image uses the same name as the standard i386 floppy.
Once you have the appropriate image file, you must copy it onto a floppy disk. You cannot use basic filesystem-level copying, such as Windows drag-and-drop, because the image files include not only files but also a filesystem. You must use appropriate tools to copy the images to a floppy.
Creating Floppies on Unix-like Systems
If you’re already running a Unix-like system, create your floppy with dd(1). You’ll need to know your floppy drive’s device name, which is probably /dev/fd0, /dev/floppy, /dev/rfd0, or /dev/rsd0 (for USB floppy drives). Once you know the device name, tell dd to copy the image to that disk device with a command like this:
# dd if=filename of=full-path-to-floppy-device
For example, to create a disk from image floppyB52.fs with the floppy device name /dev/fd0c, enter the following:
# dd if=floppyB52.fs of=/dev/fd0c
If dd gives you an error immediately or exits silently without writing to the floppy disk, try specifying a different floppy disk device.
Creating Floppies on Microsoft Systems
If you need to create a floppy on a descendant of Windows NT (including all modern Windows desktop operating systems), you’ll need an image-writing program. In the tools directory of your OpenBSD release, you’ll find a program named ntrw.exe. This program copies disk images to a disk. Download the program, open a command prompt, navigate to the folder containing ntrw.exe, put your blank floppy in the drive, and run this command:
C:> ntrw floppyB53.fs a:
If you get a permissions error, you might need to run your command prompt as Administrator. If the command still fails, chances are good that you’re using the bad floppy disk you tucked away in a drawer 15 years ago. Try another one.
Making Boot CDs
OpenBSD provides three ISO images for i386 and two for amd64, as follows:
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cdXX.iso. This image contains the kernel and installer, but no file sets. It’s used to boot a system into the minimal state where the installer can run. Once the system has booted, it fetches the file sets over the network.
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installXX.iso. This image contains everything in the cdXX.iso image, as well as the file sets. Use it to install this version of OpenBSD on multiple systems.
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cdemuXX.iso. Some older i386 systems have a BIOS that makes CD drives emulate floppy drives. If you have a system like this, use cdemuXX.iso. If you’re unsure whether you need this image, you don’t. If you’ve ever owned one of these CD drives, you’ve probably replaced it by now. If you haven’t, maybe you should.
Note
Remember that you can save yourself the trouble of selecting an ISO by buying an official CD set, which will Just Work and will also contain precompiled packages.
The process of getting the ISO onto a physical disk varies widely from operating system to operating system. On a Microsoft Windows system, right-click the ISO and select Burn to Disc. Unix-like systems use several different programs, such as burncd and cdrecord. Different Linux versions have innumerable ISO-burning front ends integrated into their desktop environments. Check online for instructions on burning a CD on your particular operating system.